The present invention is concerned with multi-dimensional scanning of a scene.
In industrial production environments, most installations and machineries are built according to plans. However, those installations and machineries tend to require upgrading over time and/or are subject to additions which may or may not be appropriately documented.
For certain applications, such as offshore platforms for instance, it is necessary when adding an additional element to be sure that it will fit in the existing installation. Other applications include scanning existing permanent structures for upgrading and/or control when no plans are readily available.
Thus, methods and apparatuses have been proposed to try and obtain “as-built” plans of these structures. Most recently, solutions involving laser digitizing apparatuses have been proposed.
Practically, those solutions imply projecting a scanning laser beam on an installation being captured. At each laser orientation, the distance is derived from the time or the phase difference in the laser to-and-fro path to a reflecting point. After suitably scanning the scene, this results in a three-dimensional set of points, also referred to as “cloud of points”, corresponding to the installation.
The scanning of the scene is usually performed as a method, which comprises:                taking a picture of the scene, selecting a scene portion to be scanned and corresponding scanning information;        scanning the scene portion according to the selected scanning information.        
When performing such a method, the desired scanning resolution defines the scanning time, and the size of the resulting data, and, accordingly, the needs in terms of hardware and software capabilities.
The applicant company has observed that this may not be entirely satisfactory in all circumstances, at it will be explained hereinafter in more details.